Received one of these from a vendor recently. Thought it was great, essentially leak proof within reason when held upright, cool little doo hickey to keep the straw from popping out the top, then I filled 'er up and took her in the car. The rattle from the hard straw banging around made me crazy. Then my son managed to snap the straw in pieces just by banging it around inside the cup. Totally useless in a span of about 15 minutes. But if you’re hard of hearing and have an unusually light touch, damn the torpedos, full steam ahead.